Erika's Page

The Digestion SystemDigestion:Digestion is the body's process of breaking down food into its simplest form and converting them into energy for the body. Foods that contain carbohydrates, such as pasta, are simplified first, and broken down into glucose. Foods that contain protein, animal byproducts, are simplified, and broken down into amino acids. Finally, foods that contains fats, such a ice cream and cheese, are simplified and broken down into free floating fatty aids. Carbohydrates are broken down first, due to the salivary amylase glands in the mouth , which release enzymes that break down starches before digestion begins. Protein digestion occurs in the stomach when the enzyme of pepsin begins to break down the protein into amino acids. Fat digestion, is the slowest food staple to digest, however when the body finally breaks the lipids down they simplify into free floating amino acids.The Digestion Track:1) The digestion process begins in the mouth, where salivary amylase begin to break down food before it enters into the esophagus, and turns the newly digested food into a bolus.2) The bolus then travels past the pharynx, where muscles contract and relax to move food into the esophagus.3) Once in the esophagus the bolus is taken down into the stomach by a process know as peristalsis, or the contraction and relaxation of muscles in the esophagus.4) After the bolus travels through the walls of the esophagus it enters into the stomach where nutrients are absorbed through the stomach walls. In the stomach food is also mixed with HCL and pepsin, two enzymes that turn the bolus into chyme, or a thick and soupy liquid that travels though the rest of the digestion system. Besides HCL and pepsin, gastric juices, which are released by gastric glands, help further digest the digested food until it is ready to move on to the small intestine. Food usually remains in the stomach for 2 to 6 hours, until it is fully digested, and ready to move on.5) One the food is in the small intestine, it travels through be peristalsis, which is the contraction and relaxation of muscles, and is further broken down by bile. In the small intestine, bile, which is stored in the pancreas and liver, enters into the small intestine and is responsible for emulsification, or the break down of food into more nutrients for the body. Besides peristalsis, finger like hairs, called villi, help move the digested food along to the larger intestine.6) Once in the large intestine, the food is being prepared to depart from the body. In the large intestine water, salts, and vitamins are absorbed, during their last stage of digestion, until the food in ready to be eliminated from the body.

Digestion Simplified...

Digestive organs:The digestive system is a complex system in which many organs must work together to achieve the over all goal of food digestion:1) The mouth/tongue- food is chewed and broken by the teeth, and then uses the tongue to begin the chemical digestion2) Salivary glands- when the chewed up food reaches the tongue, glands in the mouth which produce salivary amylase that begins the true break down of the food, before it is swallowed3) The esophagus- the food enters in the esophagus by the pharynx, and travels down the esophagus by peristalsis, or the contraction and relaxation of muscles, which brings the food to the stomach4) The stomach- once the food enters the stomach, chemical digestion begins, where juices are secreted from glands on the stomach, and enzymes such as pepsin, eat protein, further simplifying the food5) The small intestine- once food is digested in the stomach and enters the small intestine, the food is broken down using bile, which comes from the liver and gallbladder and emulsifies, or breaks down the food even more, the nutrients are also absorbed into the walls of the small intestine, and are carried all over the body6) The large intestine- when the food exits the small intestine and enters into the large intestine, water, some salts, and any remaining vitamins are absorbed into the walls., food is also held here until it is ready to be eliminated
  • Accessory organs:
    • Teeth- the teeth chew the food, through a process called mastication, there are also 32 deciduous, or adult teeth
    • The pancreas- it secretes both insulin and glucagon, which help regulate levels of sugar in the blood, it also uses exocrine, or ducts to secreted enzymes that help break down food
    • The liver- by using the hepatic vein, the liver detoxes blood as it passes though, it also hold bile, which is secreted to the small intestine by the common hepatic duct
    • The gallbladder- bile is stored here, when bile is backed up it enters the cystic duct, and is stored here until needed

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Parts of the small intestine:
  • duodenum
  • jejunum
  • ileum

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Parts of the large intestine:
  • cecum
  • appendix
  • colon
  • rectum
  • anal canal
  • ascending colon
  • transcending colon
  • descending colon

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Anabolic and Catabolic Pathways...Anabolic Pathway:
When food is needed right away they are broken down in the anabolic pathway. The anabolic pathway is used to build up molecules for immediate energy. The anabolic process is the build of smaller molecules into a larger molecule. For example, when your body uses dehydration synthesis, anabolic pathways are being utilized. Dehydration synthesis is the process of creating larger molecule by removing water molecules at each bonding site. Dehydration synthesis includes the forming and building of; amino acids chains, larger sugar molecules, and carbohydrates into complex monosacharides. Catabolic Pathway:When energy is not needed by the body right away. During the catabolic pathway, food is broken down through the regular digestion process, until nutrients begin to be absorbed. The molecules of protein, fat and carbohydrates are broken down into smaller and simpler molecules that will be used for later energy creation. The stored molecules, will eventually join together, much like in the anabolic pathway, and be converted to energy for the body.




The Endocrine System

The endocrine system...

A system in the body that control the flow of the different hormones in the body. This system is the second largest controlling system in the body. Along with the nervous system, it controls and regulates different functions and reaction in the body.
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Hormones...

  • are chemical messengers that release chemicals into the blood to regulate levels in the body or catalyze other reaction

  • mainly control

    • reproduction

    • growth and development

    • mobilizing body against stressors

    • maintaining electrolyte, water, and nutrient levels in the blood

    • regulating cellular metabolism and energy system

    • nearly all of them are amino acid based molecules (including proteins, peptides, and amino acids)

    • hormones can also be classified as steroids (sex hormones), which are made form cholesterol

Target organs...

Target organs or cells are the organs that cells that are affected by certain hormones. For target cells to respond to their particular hormones specific protein receptors must be on the plasma membrane or inside, so the hormone can attach to the cell. Also, the hormone will only work if it is bonded to the organ. There are two kinds of hormones that trigger changes in cells, stroidal hormones and thyroid hormones.

  • Steroidal Hormones:

    • diffuse through the plasma membrane of the target cell
    • enter the nucleus
    • bind ot specific receptor protein
    • activate certain genes to transcrime mRNA
    • mRNA translated in the cytoplasm, resulting in the synthesis of new proteins
  • Non Steroidal Hormoens:

    • bidns to the membrane receptor

    • this stes of a series of reaction that activate an enzyme

    • that enzyme catalyzes a reaction that produces a second mesenger molecule, cyclic AMP

    • cyclic AMP oversees additional intracellular changes that promote the typical response of the target cell and hormone



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Negative feedback hormones...


Negative feedback mechanisms are the main mechanisms that regulate nearly all blood hormones. Negative feedback is can be simplified to by using two gases of water and a baster. One of the glasses represents the target organ , while the other represents the hormones. When the target organ glass of water is stimulated to need hormones the baster, or the transport mechanism of the hormones, sucks up the liquid, or hormones, form the hormone glass of water, and squirts it into the target organ glass of water. When the target organ glass of water had had enough"hormones" the baster sucks up the un-needed hormones, and brings them back to the hormone glass. A real life example of this would be parathyroid hormone. When blood calcium levels are low, PTH or parathyroid hormone is released until the calcium level is back to normal. And because too much PTH will be sent to fix the problem, the rest will return, and wait until it is needed again. Now there are three different types of hormonal stimuli that cause negative feedback: hormonal, humoral, and neural.

  • Hormonal: this is when endocrine organs are prodded by other hormones, ex: hypothalamic hormones stimulate the anterior pituitary gland to to secret its hormones

  • Humoral this is when the release in hormones is due to a change in something in the blood, ex: the PTH example above

  • Nuerual: this is when nerve fibers stimulate the release of hormones, ex: the sympathetic nervous system stimulating the adrenal medulla to release norepinephrine and epinephrine during stress


The Major Endocrine Organs...

  • the pituitary gland

    • is about the size of a grape fruit and hangs form a stalk from the inferior surface of the hypothalamus
    • had two functional lobes: the anterior pituitary (glandular tissue) and the posterior pituitary (nervous tissue)
    • main hormones of the anterior pituitary are: tropic hormones, growth hormone, prolactin, thyrotropic, adrenocorticotropic, and the two gonotropic hormones
      • all of these hormones: are proteins, act through second messenger systems, and regulate hormones by hormonal stimuli
    • main hormones of the posterior pituitaryL oxytocin and antidiurectic hormone
  • the thyroid gland

    • located at the base of the throat, just inferior to the Adam;s apple
    • consists of two lobe joined by the isthmus, or cental mass
      • these make two hormones called thyroid hormone, which can be T3 or T4 and calcitone
      • is composed of follicles, which store sticky collodial material

    • this gland produces calcitone or thyrocalcitonon
  • the parathoid gland

    • tiny masses of glandular tissue most
    • usually two gland on each thyroid lobe, for a total of four
    • this glad secretes the hormone parathyroid hormone or PTH
  • the adrenal gland

    • two bean shaped masses that are curved over the kidneys
    • has a glandular cortex and neural tissue or medulla parts
    • glanduar cortect, or adrenal cortex produce: corticodsteroids, mineralocorticoids, glucocortoids, and sex hormoens
    • the neural tissue, or adrenal medula releases: epinephrine, or adrenaline, and norepinephrine, or collectively called catecholamines
  • the pancreas

    • is located in the abdominal cavity of the stomach
    • is a mixed glad, which means is had pancreatic islets, which are little masses of hormoens producing tissue scattered among the enzyme-producing acinar tissue of the pancreas
    • also has an exocrine producing part that acts as part of the digestive system
    • produces insulin and glucagon
  • the pineal gland

    • also called the pineal body, is a small cone-shaped gland found in the roof of the third ventricle of the brain
    • The endocine, or hormone releasing part of this gland in still somewhat of a mystery
    • the hormone melatonin is the only hormone that has been found in released by this gland
  • the thymus gland

    • is located in in the upper thorax, posterior to the sternum
    • it decreases size though adulthood, and by old age is composed of connective fat and tissue
    • produces the lone hormone thymosis
  • the gonads

    • are made up of male and female organs

    • ovaries are the organ for females, and testes are the organ for males

    • ovaries are almond-sized organs located in the pelvic cavity

    • the ovaries produce estrogens, which are primarily estone and estadiol, which are produced by the Graafian follicles of the ovaries

    • the testes are suspended in a sack, the scrotum, outside the pelvic cavity

    • the testes produce androgensm which mainly produce testosterone, which is made by the interstitial cells on the testes


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The Bones

The Bones...

The bones are the bodies framework, or means of support for the body and vital organs it contains. They allow are bodies to move, and allow our limbs to rotate, flex, and extend. Without the skeletal system our muscles would have nothing to attach to, and our bodies would become gelatin like.

The function of bones:

  • Support: the bones in the leg are the main wight bearing bone, that allows our body to stand ans walk without falling over

  • Protection: bones such as the skull or vertebrae protect soft and vital organs such as the spinal cord and the brain

  • Movement: bones store essential minerals such as calcium and phosphorus, fat, that can later be later by hormones are secreted into the body when needed

  • Blood cell formation: the marrow cavities of bones are hematopoiesis, or blood cell formation occurs

The different types or classifications of bones:

In the body there are six different classifications of bones:

  • Compact Bone, which is dense and looks smooth, and homogenous

  • Spongy Bone, which is composed of small needle-like pieces of bone and lots of open space

  • Long Bone: are bones that are typically, longer than they are wide, have shafts with heads on both ends, are mostly compact, and include all of the limbs, except the write and ankle bone

  • Short Bone: are bones that are generally shaped like cubes, contain mostly spongy bone, include the bones of the wrist and ankle, and also include sesamoid bones which form within tendons (ex: patella and knee)

  • Flat Bone: are bones that are thin, flattened, usually curved, have two thin layers of compound sandwiching a layer of spongy bone between them, ex: most boned of the skull, the ribs, and the sternum (breastbone)

  • Irregular Bone: are bones that do not fit one of the preceding categories, ex: vertebratae (spinal column), and hip bone




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Markings of the bone

  • Tuberosity- large, rounded projection, may be roughened

  • Crest- narrow ridge of bone; usually prominent

  • Trochanter- very large, blunt, irregularly shaped process, the only example is the femur

  • Line- narrow ridge of bone, less prominent than a crest

  • Tubercle- small round projection or process

  • Epicondyle- raised area on or above a condyle

  • Spine- sharp, slender, often pointed projection

  • Process- and bony prominence

  • Head- bony expansion carried on a narrow neck

  • Fossa- shallow, basinlike depression in a bone, often serving as an articular surface

  • Groove- furrow

Main movers in the body:

The Skull: The skull is a bone structure made of two bones, the cranium, which is in charge of protecting the brain, and the facial bones which allow the muscles in the face to move and old the eyes in their sockets.

The cranium consists of the...

  1. Frontal bone- forms the forehead, the bony projections under the eye brows, and the superior part of the eye's orbit

  2. Parietal bone- form most of the superior and lateral walls of the cranium

  3. Temporal bones- have several important bone markings that help support and form the skull

  4. Occipital bone- forms the most posterior bone of the cranium, has the foramen magnum, which allows the spinal cord to connect to the brain

  5. Sphenoid bone- butterfly shaped bone that forms the floor of the cranium, which holds Turk's Saddle, which hold the pituitary gland

  6. Ethmoid bone- forms the roof of the nasal cavity and part of the medial walls of the orbits, also has the crista galli which is the projection that the outermost part of the brain attaches to, which also has nerve endings that attach to it.


The facial boned consist of the...

  1. Maxillae- all facial bones besides the madible join this bone, which is why it is called the keystone bone

  2. Palatine bone- form the posterior part of the hard palate(roof of the mouth

  3. Zygomatic bone- the cheek bones, also form a good portion of the lateral walls of the orbits and eye sockets

  4. Lacrimal bones- finger-like bones form part of the medial walls of each orbit, also has a groove that allows the passage of tears

  5. Nasal bone- small rectangular bones that form the bridge of the nose

  6. Vomer bone- forms most of the nasal spetum, the middle bone of the nose

  7. Inferior Nasal Cavity- the thin curved bones that form the lateral walls of the nasal cavity

  8. Mandible- the lower jaw, is the strongest bone in the face, it is the only freely moveable joints in the skull

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The Vertebral (Spine) Column- is formed of 5 sections that contain the nerves that transmit messages throughout the entire body, and help disperse weight to the lower limbs. The five sections of the spine are..

  • The Cervical Curvature (concave/ 7 vertebrae/at the top of the spine)

  • The Thoracic Curvature (convex/12 vertebrae/in the middle of the spine)

  • The Lumbar curvature (concave/5 vertebrae/at the bottom portion of the spine)

  • The Sacrum (convex/5 fused vertebrae/bottom of spine)

  • The Coccyx (4 fused vertebrae/ bottom of spine


Other important bones in the body:

  • Bones of the upper arm which form the arm, forearm, and hand

    • arm, hand, and forearm

  • The pelvis, which protects vital organ and holds the weight of the upper body

    • coxal, or hip, bone

  • The bones of the lower limbs which carry the bodies entire weight and are much thinker than the bones of the upper body because they hold the entire body upright

    • thigh, leg, and foot

  • The rib cage, or bony thorax is a protective age that protects the heart from

    • the ribs (12 ribs 7 true ribs, 5 false ribs), sternum


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Muscles

Muscles are essential tissues in the body that attach to the bones and allow the body to move and remain stable. Through contraction and lengthening, the muscles are able to move toward and away from the body.

The Three types of Muscles

Skeletal Muscle

  • packaged into skeletal muscles which attach to the bones of the body

  • made of fiber, and are tubular, striated, and multinucleated

  • their contracts are due to the nervous system

  • support the body

  • make bone marrow

  • maintains constant body temp.

  • assist movement of cardiovascular and lymphatic vessels

  • protects internal organs

  • stabilize joints

Cardiac Muscle

  • this type of muscle is from the heart

  • the fiber, which make the heart, have a single nucleus

  • the fibers are striated, tubular and branched

    • the shaped allow the fibers to interlock at intercalated disks, which permit contractions to spread quickly through the heart

Smooth Muscles

  • made of fibers

  • the fibers are shaped like spindles and each have a single nucleus

  • the cells are usually arranged in parallel lines, forming sheets of muscle

  • have no striations

  • located in the walls of hollow internal organs

  • have slower contractions (vs skeletal muscle)

  • do not tire easily

Muscle Physiology

  1. ATP (Adenosine Tri Phosphate)

    1. muscle fibers only contain a small portion of ATP

    2. provides a short term energy supply for contractions and relaxations

  2. CP (Creatine Phosphate)

    1. there is 3 to 6 times as much stored withing skeletal muscle fibers compared to ATP

    2. long term energy storage that helps quickly produce more ATP

    3. is not used for energy, but to make more ATP


  3. Muscle Fiber Glycogen

    1. long term energy source longer than CP)

How muscles can move
  • Flexion- when there is a bend at a joint and two bones come closer together (ex: bending of the knee, elbow, or hip)
  • Extension- when there is a increase in the distance between two bones
  • Rotation- when there is movement of bone around its rotational axis (this is common in ball and socket joints and describes ta movement such as shaking the head "no")
  • Abduction- when a limb moves away from the body's mid line
  • Adduction- the movement of a limb toward the middle of the body
  • Circumduction- a combination of flexion, extension, abduction, and adduction commonly seen in a ball and socket joint (ex: the shoulder) (the proximal end is stationary, and the distal end moves in a circle)

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Special Movements of the Body
  • Dorsiflexion and Plantar Flexion- lifting the foot upward to the sky is dorsiflexion, and pointing the foot and toes downward is plantar flexion
  • Inversion and Eversion- turning the foot and ankle inward to the middle of the body is inversion, and turning the foot and ankle outwards is eversion
  • Supernation and Pronation-when the palm is turned upward, or the arm is lifter upward, it is supernation, when the palm is turned to face down, or the hand is bought down, it is pronation

Origin, Insertion, and Action
Origin- the part of the muscle that is attached to the bone and is immovable or less moveable

Insertion - the part of the muscle that is attached to the moveable bone, and when the muscle contracts it moves toward the origin

Action- the movements the muscle performs

Examples of muscles:
Muscle
Origin
Insertion
Action
Trapezius
Occipital bone and cervical/thoracic vertebrae
Scapular spine and clavicle
Extends neck and adducts scapula
Deltoid
Scapular spine and clavicle
Humerus (deltoid turberosity)
Abducts humerus
Latissimus Dorsi
Lower spine and iliac crest
Proximal humerus
Extends and adducts humerus
Rectus Abdominis
Pubis
Sternum and 5ht to 6th
Flexes vertebral column
Pectoralis Major/Minor
Sternum, clavicle, and first to 6th ribs
Proximal humerus
Adducts and flexes humerus
Bicep Brachii
Scapula of shoulder girdle
Proximal radius
Flexes elbow and supinates forearm
Brachialis
Distal humerus
Proximal ulna
Flexes elbow
Triceps brachi
Shoulder girdle and proximal humerus
Olecranon process of ulna
Extends elbow
Flexor carpi radialis
Distal humerus
2nd 3rd metecarpal
Flexes wrist and abducts hand
Flexor carpi ulnaris
Distal humerus and posterior ulna
Carpals of wrist and 5th metacarpals
Flexes wrists and adducts hand
Adductor muscles
Pelvis
Proximal femur
Adduct thigh
Quadriceps-
vastus medialis, intermedius, lateralis: and the rectus femoris
Femur
Rectus femoris: pelvis
Tibial tuberosity via patellar ligament
Extend the knee
Rectus Femoris: also flexes hip on thigh
Hamstrings- semitendinosus, semimembranosus, biceps femoris
Ischial tuberosity
Proximal tibia (head of fibula in the case of biceps femoris)
Flex knee and extend hip
Gastocnemius
Distal femur
Calcaneus (heel via calcaneal tendon)
Plantar flexes foot and flexes knee
Soleus
Proximal tibia and fibula
Calcaneus
Plantar flexes foot
Gluteus maximus
Sacrum and ilium
Proximal femur (gluteal tuberosity)
Extends hip (when forceful extension is required)
Gluteus mediusMotor neurs
IIium
Proximal femur
Abducts thigh: steadies pelvis during walking


Sliding Filament Theory- the process that describes and explains the way that muscles relax and contract during a movement

  1. Motor neurons in the muscle send a signal to the muscle fibers, causing a chemical signal to occur, which releases calcium into the area around the sacromere
  2. As the calcium levels rise, the ions bind to to regulatory sites on troponin, causing it to change shape, causing tropomyosin to move deeper into the actin, and away from the myosin binding sites, removing the blockade
  3. Cross bridge formation occurs next, this is when myosin heads are strongly attracted to the exposed binding sites on the actin, forming a cross bridge
  4. The power stroke is next, which occurs as the myosin head binds, phosphate generated during the prior contraction cycle is released, casing the power stroke, during this process the myosin head pivots which pulls the thin actin filament towards the sacromere. At the same time, ADP generated during the prior contraction is released.
  5. Cross bridge detachment,